Devices used in medical fields may be indwelled in contact with blood in or on bodies of various living organisms including human beings (hereinafter referred to as “indwelling device”) Examples of the indwelling device include stents, catheters, balloons, vascular prostheses, artificial blood vessels, artificial skins, transdermal devices, adhesion-preventing materials, and wound dressings.
Stents are used in treatment of, for example, stenosis and occlusion of body lumens such as blood vessels, bile ducts, tracheas, esophagi, alimentary canal, ureters, and urethras in living bodies. Specifically, the stents are hollow tubes which can be indwelled on lesions such as stenosis and occlusion of body lumens to dilate the lumens and keep them open in treatment of various disorders due to stenosis or occlusion of body lumens such as blood vessels. For example, stents are used in cardiac coronary arteries to prevent restenosis after percutaneous transluminal coronary angioplasty (PTCA). Dwelling such stents in body lumens such as blood vessels after surgery can reduce incidence of acute vascular occlusion and restenosis.
Conventionally, various metals or resins have been used for stents in view of durability and expandability.
These materials, however, have a problem in that blood adheres to surfaces of the stents and clots over time.
To solve such a problem, techniques have been proposed to coat the surfaces of stents with various resins in order to prevent blood coagulation (for example, Patent Documents 1 to 4).
[Patent Document 1] International publication No. WO2003/090807
[Patent Document 2] International publication No. WO2003/080147
[Patent Document 3] U.S. Pat. No. 6,211,249
[Patent Document 4] International publication No. WO99/02168